Ovens of this type comprise a box-shaped housing provided with electrical heating resistors arranged at their upper and lower walls. Such ovens define a single baking chamber and therefore are of very restricted capacity. In fact, such ovens are often very small.
Moreover, despite the small size, the distance between the upper and lower resistors is too much to allow baking sliced bread on both faces evenly, quickly and with a low energy consumption.
Multiple baking-chamber ovens have been developed in order to increase the oven capacity and reduce the distance of resistors from the sliced bread.
Such ovens have an inside intermediate wall which usually delimits two baking chambers reciprocally superimposed.
Moreover, in order to ensure good irradiation and therefore sufficiently quick and even baking or heating, traditional ovens are provided with additional resistors arranged at each of the two faces of the intermediate wall.
However, traditional ovens have several disadvantages that are apparent both during use and during manufacture.
In fact in the first case the advantages mainly relate to the high electrical consumption caused by the dual central resistor and to the great difficulty of cleaning the baking chambers, since the resistors mounted on the intermediate wall hinder access to same and make access to the farthest edges from the access port very difficult.
Moreover, sliced bread must be arranged as close as possible to the resistors to optimize toasting. This implies that in such ovens it is not possible to bake other foodstuff besides slices of bread. In fact, due to the limited distance between the foodstuff to bake and the resistors, and due to the high temperatures at which the same resistors are brought, traditional ovens are not suitable for baking anything other than slices of bread.
With products that are not sliced bread, in fact, it is necessary to heat very slowly so as to optimise thermal diffusion from outer to inner regions in order to prevent burning the surface of the foodstuff being baked before heat diffuses inside it for a complete baking of the product, due to the high resistor temperature.
On the other hand in the second case, the fact of having to provide intermediate wall in the oven housing and two electrical resistors requires several additional manufacturing steps and costs due to the higher number of elements used.